@abergeron thanks for sharing the code, it was helpful to get me started. It looks like you used this code to send some information from the Arduino to the Robot controller, right?
What I need to do is to send a couple of binary coils and a couple of analog registers to the Arduino so that it can control the stepper motors accordingly.
I am also running into some problems testing even the most basic Modbus setup with a simulator. I described my problem in another post.
Thank you!